Sun-Earth Day Presents: Eclipse, In a Different Light

TECHNOLOGY THROUGH TIME

Since the first records of solar eclipses were made on clay tablets by the ancient Sumerians, this magnificent wonder of the natural world has produced both wonderment and fear among earth-bound watchers. Across the centuries, and across the continents, the steady improvement in how eclipses are rendered and observed has led to some surprising discoveries.
The corona, at first considered the atmosphere of the moon, became recognized as the atmosphere of the sun. By the mid-1800s, the first attempts at photography captured the corona's myriad shapes and details. The race was on, to understand what this ephemeral substance might be. Spectroscopes detected a new element 'coronium' now recognized as the light from iron atoms heated to 100,000 C or more. By the turn of the 20th century, spectroheliographs could isolate the light from individual elements in the solar atmosphere, and transform them into pictures of the sun at different wavelenths. Then, by the mid-1900s, astronomers created the first artifial solar eclipses using coronagraphs. For the first time the corona could be studied at will, and the need for total solar eclipses as a scientific tool began to wane in importance.

Meanwhile, as the scientific questions about the sun grew in number and subtlety, scientists working with NASA since the dawn of the Space Age, developed still more exotic instruments to study the sun in ever-increasing detail. New insights about its stormy countenance, its sunspot cycles, and its interior structure began to emerge each year. Beyond heat and light, we now see the sun as a more complex player in the affairs of our own world. It can modify our climate, cause disruptions to our technology, and can even affect our health under certain conditions. This newer appreciation of our sun and its occasional tantrums has been hard-won, and the product of thousands of observers and scientists across the centuries. As we look to the future, we can only wonder what new discoveries await us.